Twin spool valve assemblies are used in hydraulic power systems for controlling hydraulic fluid flow to work components such as hydraulic cylinders. A twin spool valve assembly can include first and second spools that are moved within corresponding spool bores of the valve assembly to alternatingly place corresponding first and second work ports of the of the valve assembly in fluid communication with either pump system pressure or tank pressure. In operation, a powered actuator (e.g., a solenoid arrangement, voice coil arrangement, pilot valve arrangement, etc.) can coordinate movement of the first and second spools within their corresponding spool bores such that when the first work port is in fluid communication with pump system pressure, the second work port is in fluid communication with tank pressure, and when the first work port is in fluid communication with lank pressure, the second pork port is in fluid communication with pump system pressure. The first and second work ports can be respectively coupled to first and second ports of a work component such that pump system pressure from the hydraulic power system can be used to drive movement of the work component.
US 2013/0048893 discloses an example twin spool valve assembly having a manual override for allowing the positions of the twin spools to be manually adjusted in the event of failure of the powered actuator. In this way, movement of the corresponding work component can be manually controlled in situations where the powered actuator is not operational.
Existing manual overrides can be subject to wear and can be relatively complicated in design (i.e., can include a relatively large number of separate parts that need to be assembled) thereby increasing manufacturing and installation costs. It would be beneficial to provide for a spool assembly and retainer plug assembly comprising fewer parts than the currently available assemblies. It would further be beneficial to provide for a spool assembly and retainer plug assembly that are more cost effective to manufacture and easier to assemble.